From e46ef1db9e2c87d5aa13a04ea2329b8bae7ea9db Mon Sep 17 00:00:00 2001
From: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Date: Sat, 19 Mar 2022 06:35:43 +0100
Subject: efi_loader: efi_dp_find_obj() add protocol check

Let function efi_dp_find_obj() additionally check if a given protocol is
installed on the handle relating to the device-path.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
---
 lib/efi_loader/efi_boottime.c    |  2 +-
 lib/efi_loader/efi_capsule.c     |  2 +-
 lib/efi_loader/efi_device_path.c | 23 ++++++++++++++++-------
 lib/efi_loader/efi_disk.c        |  2 +-
 4 files changed, 19 insertions(+), 10 deletions(-)

(limited to 'lib')

diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index d0f3e05e708..a7bc371f541 100644
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -1750,7 +1750,7 @@ efi_status_t efi_setup_loaded_image(struct efi_device_path *device_path,
 	info->system_table = &systab;
 
 	if (device_path) {
-		info->device_handle = efi_dp_find_obj(device_path, NULL);
+		info->device_handle = efi_dp_find_obj(device_path, NULL, NULL);
 
 		dp = efi_dp_append(device_path, file_path);
 		if (!dp) {
diff --git a/lib/efi_loader/efi_capsule.c b/lib/efi_loader/efi_capsule.c
index 613b531b825..011942bbb79 100644
--- a/lib/efi_loader/efi_capsule.c
+++ b/lib/efi_loader/efi_capsule.c
@@ -680,7 +680,7 @@ static bool device_is_present_and_system_part(struct efi_device_path *dp)
 {
 	efi_handle_t handle;
 
-	handle = efi_dp_find_obj(dp, NULL);
+	handle = efi_dp_find_obj(dp, NULL, NULL);
 	if (!handle)
 		return false;
 
diff --git a/lib/efi_loader/efi_device_path.c b/lib/efi_loader/efi_device_path.c
index aeb52648200..0a8802903d7 100644
--- a/lib/efi_loader/efi_device_path.c
+++ b/lib/efi_loader/efi_device_path.c
@@ -160,17 +160,19 @@ struct efi_device_path *efi_dp_shorten(struct efi_device_path *dp)
 }
 
 /**
- * find_handle() - find handle by device path
+ * find_handle() - find handle by device path and installed protocol
  *
  * If @rem is provided, the handle with the longest partial match is returned.
  *
  * @dp:		device path to search
+ * @guid:	GUID of protocol that must be installed on path or NULL
  * @short_path:	use short form device path for matching
  * @rem:	pointer to receive remaining device path
  * Return:	matching handle
  */
-static efi_handle_t find_handle(struct efi_device_path *dp, bool short_path,
-			        struct efi_device_path **rem)
+static efi_handle_t find_handle(struct efi_device_path *dp,
+				const efi_guid_t *guid, bool short_path,
+				struct efi_device_path **rem)
 {
 	efi_handle_t handle, best_handle = NULL;
 	efi_uintn_t len, best_len = 0;
@@ -183,6 +185,11 @@ static efi_handle_t find_handle(struct efi_device_path *dp, bool short_path,
 		efi_uintn_t len_current;
 		efi_status_t ret;
 
+		if (guid) {
+			ret = efi_search_protocol(handle, guid, &handler);
+			if (ret != EFI_SUCCESS)
+				continue;
+		}
 		ret = efi_search_protocol(handle, &efi_guid_device_path,
 					  &handler);
 		if (ret != EFI_SUCCESS)
@@ -195,13 +202,13 @@ static efi_handle_t find_handle(struct efi_device_path *dp, bool short_path,
 		}
 		len_current = efi_dp_instance_size(dp_current);
 		if (rem) {
-			if (len_current < len)
+			if (len_current > len)
 				continue;
 		} else {
 			if (len_current != len)
 				continue;
 		}
-		if (memcmp(dp_current, dp, len))
+		if (memcmp(dp_current, dp, len_current))
 			continue;
 		if (!rem)
 			return handle;
@@ -220,18 +227,20 @@ static efi_handle_t find_handle(struct efi_device_path *dp, bool short_path,
  * If @rem is provided, the handle with the longest partial match is returned.
  *
  * @dp:		device path to search
+ * @guid:	GUID of protocol that must be installed on path or NULL
  * @rem:	pointer to receive remaining device path
  * Return:	matching handle
  */
 efi_handle_t efi_dp_find_obj(struct efi_device_path *dp,
+			     const efi_guid_t *guid,
 			     struct efi_device_path **rem)
 {
 	efi_handle_t handle;
 
-	handle = find_handle(dp, false, rem);
+	handle = find_handle(dp, guid, false, rem);
 	if (!handle)
 		/* Match short form device path */
-		handle = find_handle(dp, true, rem);
+		handle = find_handle(dp, guid, true, rem);
 
 	return handle;
 }
diff --git a/lib/efi_loader/efi_disk.c b/lib/efi_loader/efi_disk.c
index 45127d17686..d36a35d94fe 100644
--- a/lib/efi_loader/efi_disk.c
+++ b/lib/efi_loader/efi_disk.c
@@ -302,7 +302,7 @@ efi_fs_from_path(struct efi_device_path *full_path)
 	efi_free_pool(file_path);
 
 	/* Get the EFI object for the partition */
-	efiobj = efi_dp_find_obj(device_path, NULL);
+	efiobj = efi_dp_find_obj(device_path, NULL, NULL);
 	efi_free_pool(device_path);
 	if (!efiobj)
 		return NULL;
-- 
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